<?php
/**
 * CModel class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */


/**
 * CModel is the base class providing the common features needed by data model objects.
 *
 * CModel defines the basic framework for data models that need to be validated.
 *
 * @property CList $validatorList All the validators declared in the model.
 * @property array $validators The validators applicable to the current {@link scenario}.
 * @property array $errors Errors for all attributes or the specified attribute. Empty array is returned if no error.
 * @property array $attributes Attribute values (name=>value).
 * @property string $scenario The scenario that this model is in.
 * @property array $safeAttributeNames Safe attribute names.
 * @property CMapIterator $iterator An iterator for traversing the items in the list.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.base
 * @since 1.0
 */
abstract class CModel extends CComponent implements IteratorAggregate, ArrayAccess
{
    private $_errors = array();    // attribute name => array of errors
    private $_validators;        // validators
    private $_scenario = '';    // scenario

    /**
     * Returns the list of attribute names of the model.
     * @return array list of attribute names.
     */
    abstract public function attributeNames();

    /**
     * Returns the validation rules for attributes.
     *
     * This method should be overridden to declare validation rules.
     * Each rule is an array with the following structure:
     * <pre>
     * array('attribute list', 'validator name', 'on'=>'scenario name', ...validation parameters...)
     * </pre>
     * where
     * <ul>
     * <li>attribute list: specifies the attributes (separated by commas) to be validated;</li>
     * <li>validator name: specifies the validator to be used. It can be the name of a model class
     *   method, the name of a built-in validator, or a validator class (or its path alias).
     *   A validation method must have the following signature:
     * <pre>
     * // $params refers to validation parameters given in the rule
     * function validatorName($attribute,$params)
     * </pre>
     *   A built-in validator refers to one of the validators declared in {@link CValidator::builtInValidators}.
     *   And a validator class is a class extending {@link CValidator}.</li>
     * <li>on: this specifies the scenarios when the validation rule should be performed.
     *   Separate different scenarios with commas. If this option is not set, the rule
     *   will be applied in any scenario that is not listed in "except". Please see {@link scenario} for more details about this option.</li>
     * <li>except: this specifies the scenarios when the validation rule should not be performed.
     *   Separate different scenarios with commas. Please see {@link scenario} for more details about this option.</li>
     * <li>additional parameters are used to initialize the corresponding validator properties.
     *   Please refer to individal validator class API for possible properties.</li>
     * </ul>
     *
     * The following are some examples:
     * <pre>
     * array(
     *     array('username', 'required'),
     *     array('username', 'length', 'min'=>3, 'max'=>12),
     *     array('password', 'compare', 'compareAttribute'=>'password2', 'on'=>'register'),
     *     array('password', 'authenticate', 'on'=>'login'),
     * );
     * </pre>
     *
     * Note, in order to inherit rules defined in the parent class, a child class needs to
     * merge the parent rules with child rules using functions like array_merge().
     *
     * @return array validation rules to be applied when {@link validate()} is called.
     * @see scenario
     */
    public function rules()
    {
        return array();
    }

    /**
     * Returns a list of behaviors that this model should behave as.
     * The return value should be an array of behavior configurations indexed by
     * behavior names. Each behavior configuration can be either a string specifying
     * the behavior class or an array of the following structure:
     * <pre>
     * 'behaviorName'=>array(
     *     'class'=>'path.to.BehaviorClass',
     *     'property1'=>'value1',
     *     'property2'=>'value2',
     * )
     * </pre>
     *
     * Note, the behavior classes must implement {@link IBehavior} or extend from
     * {@link CBehavior}. Behaviors declared in this method will be attached
     * to the model when it is instantiated.
     *
     * For more details about behaviors, see {@link CComponent}.
     * @return array the behavior configurations (behavior name=>behavior configuration)
     */
    public function behaviors()
    {
        return array();
    }

    /**
     * Returns the attribute labels.
     * Attribute labels are mainly used in error messages of validation.
     * By default an attribute label is generated using {@link generateAttributeLabel}.
     * This method allows you to explicitly specify attribute labels.
     *
     * Note, in order to inherit labels defined in the parent class, a child class needs to
     * merge the parent labels with child labels using functions like array_merge().
     *
     * @return array attribute labels (name=>label)
     * @see generateAttributeLabel
     */
    public function attributeLabels()
    {
        return array();
    }

    /**
     * Performs the validation.
     *
     * This method executes the validation rules as declared in {@link rules}.
     * Only the rules applicable to the current {@link scenario} will be executed.
     * A rule is considered applicable to a scenario if its 'on' option is not set
     * or contains the scenario.
     *
     * Errors found during the validation can be retrieved via {@link getErrors}.
     *
     * @param array $attributes list of attributes that should be validated. Defaults to null,
     * meaning any attribute listed in the applicable validation rules should be
     * validated. If this parameter is given as a list of attributes, only
     * the listed attributes will be validated.
     * @param boolean $clearErrors whether to call {@link clearErrors} before performing validation
     * @return boolean whether the validation is successful without any error.
     * @see beforeValidate
     * @see afterValidate
     */
    public function validate($attributes = null, $clearErrors = true)
    {
        if ($clearErrors)
            $this->clearErrors();
        if ($this->beforeValidate()) {
            foreach ($this->getValidators() as $validator)
                $validator->validate($this, $attributes);
            $this->afterValidate();
            return !$this->hasErrors();
        } else
            return false;
    }

    /**
     * This method is invoked after a model instance is created by new operator.
     * The default implementation raises the {@link onAfterConstruct} event.
     * You may override this method to do postprocessing after model creation.
     * Make sure you call the parent implementation so that the event is raised properly.
     */
    protected function afterConstruct()
    {
        if ($this->hasEventHandler('onAfterConstruct'))
            $this->onAfterConstruct(new CEvent($this));
    }

    /**
     * This method is invoked before validation starts.
     * The default implementation calls {@link onBeforeValidate} to raise an event.
     * You may override this method to do preliminary checks before validation.
     * Make sure the parent implementation is invoked so that the event can be raised.
     * @return boolean whether validation should be executed. Defaults to true.
     * If false is returned, the validation will stop and the model is considered invalid.
     */
    protected function beforeValidate()
    {
        $event = new CModelEvent($this);
        $this->onBeforeValidate($event);
        return $event->isValid;
    }

    /**
     * This method is invoked after validation ends.
     * The default implementation calls {@link onAfterValidate} to raise an event.
     * You may override this method to do postprocessing after validation.
     * Make sure the parent implementation is invoked so that the event can be raised.
     */
    protected function afterValidate()
    {
        $this->onAfterValidate(new CEvent($this));
    }

    /**
     * This event is raised after the model instance is created by new operator.
     * @param CEvent $event the event parameter
     */
    public function onAfterConstruct($event)
    {
        $this->raiseEvent('onAfterConstruct', $event);
    }

    /**
     * This event is raised before the validation is performed.
     * @param CModelEvent $event the event parameter
     */
    public function onBeforeValidate($event)
    {
        $this->raiseEvent('onBeforeValidate', $event);
    }

    /**
     * This event is raised after the validation is performed.
     * @param CEvent $event the event parameter
     */
    public function onAfterValidate($event)
    {
        $this->raiseEvent('onAfterValidate', $event);
    }

    /**
     * Returns all the validators declared in the model.
     * This method differs from {@link getValidators} in that the latter
     * would only return the validators applicable to the current {@link scenario}.
     * Also, since this method return a {@link CList} object, you may
     * manipulate it by inserting or removing validators (useful in behaviors).
     * For example, <code>$model->validatorList->add($newValidator)</code>.
     * The change made to the {@link CList} object will persist and reflect
     * in the result of the next call of {@link getValidators}.
     * @return CList all the validators declared in the model.
     * @since 1.1.2
     */
    public function getValidatorList()
    {
        if ($this->_validators === null)
            $this->_validators = $this->createValidators();
        return $this->_validators;
    }

    /**
     * Returns the validators applicable to the current {@link scenario}.
     * @param string $attribute the name of the attribute whose validators should be returned.
     * If this is null, the validators for ALL attributes in the model will be returned.
     * @return array the validators applicable to the current {@link scenario}.
     */
    public function getValidators($attribute = null)
    {
        if ($this->_validators === null)
            $this->_validators = $this->createValidators();

        $validators = array();
        $scenario = $this->getScenario();
        foreach ($this->_validators as $validator) {
            if ($validator->applyTo($scenario)) {
                if ($attribute === null || in_array($attribute, $validator->attributes, true))
                    $validators[] = $validator;
            }
        }
        return $validators;
    }

    /**
     * Creates validator objects based on the specification in {@link rules}.
     * This method is mainly used internally.
     * @throws CException if current class has an invalid validation rule
     * @return CList validators built based on {@link rules()}.
     */
    public function createValidators()
    {
        $validators = new CList;
        foreach ($this->rules() as $rule) {
            if (isset($rule[0], $rule[1]))  // attributes, validator name
                $validators->add(CValidator::createValidator($rule[1], $this, $rule[0], array_slice($rule, 2)));
            else
                throw new CException(Yii::t('yii', '{class} has an invalid validation rule. The rule must specify attributes to be validated and the validator name.',
                    array('{class}' => get_class($this))));
        }
        return $validators;
    }

    /**
     * Returns a value indicating whether the attribute is required.
     * This is determined by checking if the attribute is associated with a
     * {@link CRequiredValidator} validation rule in the current {@link scenario}.
     * @param string $attribute attribute name
     * @return boolean whether the attribute is required
     */
    public function isAttributeRequired($attribute)
    {
        foreach ($this->getValidators($attribute) as $validator) {
            if ($validator instanceof CRequiredValidator)
                return true;
        }
        return false;
    }

    /**
     * Returns a value indicating whether the attribute is safe for massive assignments.
     * @param string $attribute attribute name
     * @return boolean whether the attribute is safe for massive assignments
     * @since 1.1
     */
    public function isAttributeSafe($attribute)
    {
        $attributes = $this->getSafeAttributeNames();
        return in_array($attribute, $attributes);
    }

    /**
     * Returns the text label for the specified attribute.
     * @param string $attribute the attribute name
     * @return string the attribute label
     * @see generateAttributeLabel
     * @see attributeLabels
     */
    public function getAttributeLabel($attribute)
    {
        $labels = $this->attributeLabels();
        if (isset($labels[$attribute]))
            return $labels[$attribute];
        else
            return $this->generateAttributeLabel($attribute);
    }

    /**
     * Returns a value indicating whether there is any validation error.
     * @param string $attribute attribute name. Use null to check all attributes.
     * @return boolean whether there is any error.
     */
    public function hasErrors($attribute = null)
    {
        if ($attribute === null)
            return $this->_errors !== array();
        else
            return isset($this->_errors[$attribute]);
    }

    /**
     * Returns the errors for all attribute or a single attribute.
     * @param string $attribute attribute name. Use null to retrieve errors for all attributes.
     * @return array errors for all attributes or the specified attribute. Empty array is returned if no error.
     */
    public function getErrors($attribute = null)
    {
        if ($attribute === null)
            return $this->_errors;
        else
            return isset($this->_errors[$attribute]) ? $this->_errors[$attribute] : array();
    }

    /**
     * Returns the first error of the specified attribute.
     * @param string $attribute attribute name.
     * @return string the error message. Null is returned if no error.
     */
    public function getError($attribute)
    {
        return isset($this->_errors[$attribute]) ? reset($this->_errors[$attribute]) : null;
    }

    /**
     * Adds a new error to the specified attribute.
     * @param string $attribute attribute name
     * @param string $error new error message
     */
    public function addError($attribute, $error)
    {
        $this->_errors[$attribute][] = $error;
    }

    /**
     * Adds a list of errors.
     * @param array $errors a list of errors. The array keys must be attribute names.
     * The array values should be error messages. If an attribute has multiple errors,
     * these errors must be given in terms of an array.
     * You may use the result of {@link getErrors} as the value for this parameter.
     */
    public function addErrors($errors)
    {
        foreach ($errors as $attribute => $error) {
            if (is_array($error)) {
                foreach ($error as $e)
                    $this->addError($attribute, $e);
            } else
                $this->addError($attribute, $error);
        }
    }

    /**
     * Removes errors for all attributes or a single attribute.
     * @param string $attribute attribute name. Use null to remove errors for all attribute.
     */
    public function clearErrors($attribute = null)
    {
        if ($attribute === null)
            $this->_errors = array();
        else
            unset($this->_errors[$attribute]);
    }

    /**
     * Generates a user friendly attribute label.
     * This is done by replacing underscores or dashes with blanks and
     * changing the first letter of each word to upper case.
     * For example, 'department_name' or 'DepartmentName' becomes 'Department Name'.
     * @param string $name the column name
     * @return string the attribute label
     */
    public function generateAttributeLabel($name)
    {
        return ucwords(trim(strtolower(str_replace(array('-', '_', '.'), ' ', preg_replace('/(?<![A-Z])[A-Z]/', ' \0', $name)))));
    }

    /**
     * Returns all attribute values.
     * @param array $names list of attributes whose value needs to be returned.
     * Defaults to null, meaning all attributes as listed in {@link attributeNames} will be returned.
     * If it is an array, only the attributes in the array will be returned.
     * @return array attribute values (name=>value).
     */
    public function getAttributes($names = null)
    {
        $values = array();
        foreach ($this->attributeNames() as $name)
            $values[$name] = $this->$name;

        if (is_array($names)) {
            $values2 = array();
            foreach ($names as $name)
                $values2[$name] = isset($values[$name]) ? $values[$name] : null;
            return $values2;
        } else
            return $values;
    }

    /**
     * Sets the attribute values in a massive way.
     * @param array $values attribute values (name=>value) to be set.
     * @param boolean $safeOnly whether the assignments should only be done to the safe attributes.
     * A safe attribute is one that is associated with a validation rule in the current {@link scenario}.
     * @see getSafeAttributeNames
     * @see attributeNames
     */
    public function setAttributes($values, $safeOnly = true)
    {
        if (!is_array($values))
            return;
        $attributes = array_flip($safeOnly ? $this->getSafeAttributeNames() : $this->attributeNames());
        foreach ($values as $name => $value) {
            if (isset($attributes[$name]))
                $this->$name = $value;
            elseif ($safeOnly)
                $this->onUnsafeAttribute($name, $value);
        }
    }

    /**
     * Sets the attributes to be null.
     * @param array $names list of attributes to be set null. If this parameter is not given,
     * all attributes as specified by {@link attributeNames} will have their values unset.
     * @since 1.1.3
     */
    public function unsetAttributes($names = null)
    {
        if ($names === null)
            $names = $this->attributeNames();
        foreach ($names as $name)
            $this->$name = null;
    }

    /**
     * This method is invoked when an unsafe attribute is being massively assigned.
     * The default implementation will log a warning message if YII_DEBUG is on.
     * It does nothing otherwise.
     * @param string $name the unsafe attribute name
     * @param mixed $value the attribute value
     * @since 1.1.1
     */
    public function onUnsafeAttribute($name, $value)
    {
        if (YII_DEBUG)
            Yii::log(Yii::t('yii', 'Failed to set unsafe attribute "{attribute}" of "{class}".', array('{attribute}' => $name, '{class}' => get_class($this))), CLogger::LEVEL_WARNING);
    }

    /**
     * Returns the scenario that this model is used in.
     *
     * Scenario affects how validation is performed and which attributes can
     * be massively assigned.
     *
     * A validation rule will be performed when calling {@link validate()}
     * if its 'except' value does not contain current scenario value while
     * 'on' option is not set or contains the current scenario value.
     *
     * And an attribute can be massively assigned if it is associated with
     * a validation rule for the current scenario. Note that an exception is
     * the {@link CUnsafeValidator unsafe} validator which marks the associated
     * attributes as unsafe and not allowed to be massively assigned.
     *
     * @return string the scenario that this model is in.
     */
    public function getScenario()
    {
        return $this->_scenario;
    }

    /**
     * Sets the scenario for the model.
     * @param string $value the scenario that this model is in.
     * @see getScenario
     */
    public function setScenario($value)
    {
        $this->_scenario = $value;
    }

    /**
     * Returns the attribute names that are safe to be massively assigned.
     * A safe attribute is one that is associated with a validation rule in the current {@link scenario}.
     * @return array safe attribute names
     */
    public function getSafeAttributeNames()
    {
        $attributes = array();
        $unsafe = array();
        foreach ($this->getValidators() as $validator) {
            if (!$validator->safe) {
                foreach ($validator->attributes as $name)
                    $unsafe[] = $name;
            } else {
                foreach ($validator->attributes as $name)
                    $attributes[$name] = true;
            }
        }

        foreach ($unsafe as $name)
            unset($attributes[$name]);
        return array_keys($attributes);
    }

    /**
     * Returns an iterator for traversing the attributes in the model.
     * This method is required by the interface IteratorAggregate.
     * @return CMapIterator an iterator for traversing the items in the list.
     */
    public function getIterator()
    {
        $attributes = $this->getAttributes();
        return new CMapIterator($attributes);
    }

    /**
     * Returns whether there is an element at the specified offset.
     * This method is required by the interface ArrayAccess.
     * @param mixed $offset the offset to check on
     * @return boolean
     */
    public function offsetExists($offset)
    {
        return property_exists($this, $offset);
    }

    /**
     * Returns the element at the specified offset.
     * This method is required by the interface ArrayAccess.
     * @param integer $offset the offset to retrieve element.
     * @return mixed the element at the offset, null if no element is found at the offset
     */
    public function offsetGet($offset)
    {
        return $this->$offset;
    }

    /**
     * Sets the element at the specified offset.
     * This method is required by the interface ArrayAccess.
     * @param integer $offset the offset to set element
     * @param mixed $item the element value
     */
    public function offsetSet($offset, $item)
    {
        $this->$offset = $item;
    }

    /**
     * Unsets the element at the specified offset.
     * This method is required by the interface ArrayAccess.
     * @param mixed $offset the offset to unset element
     */
    public function offsetUnset($offset)
    {
        unset($this->$offset);
    }
}
